Katy Perry's new single opens with a 'Roar'

Katy Perry, shown during a visit to a New York radio station, has a hit with her song "Roar," but fans have noticed similarities between her new single and Sara Bareilles' song "Brave."

Katy Perry, shown during a visit to a New York radio station, has a hit with her song "Roar," but fans have noticed similarities between her new single and Sara Bareilles' song "Brave." (Craig Barritt / Getty Images)

Gerrick D. KennedyA correction has been added to this post, as indicated below.

The lead single from the pop vixen’s upcoming album sold 557,000 downloads in its first week of release, according to Nielsen SoundScan, making it the biggest digital sales week of any song this year.

Perry also bested two other singles milestones of her own. The song edged out her hit “Firework” for one-week sales (the 2010 hit moved 509,000 downloads in one week), and topped her previous highest digital debut, “Part Of Me,” which opened with 411,000 downloads when it was released early last year.

“Roar” is Perry at her finest: delivering a sweet, poppy confection with a bit of bite.

The single -- courtesy of frequent collaborators and pop masterminds Dr. Luke and Max Martin -- doesn’t pack the same brazen, fiery edge of previous post-divorce singles such as “Wide Awake” and “Part of Me,” but Perry’s knack for crafting ubiquitous pop anthems remains untouched.

“Roar” doesn’t come without controversy, as fans and critics have pointed out the song's similar feel to Sara Bareilles' hit "Brave."

In promo clips for the single, Perry is shedding her pin-up, candy-coated image, so fans shouldn’t expect to see her prancing around in a blue wig and a spinning lollipop bra when she closes the MTV Video Music Awards on Sunday with the first live performance of “Roar.”

Perry’s latest hit is lifted from her upcoming fourth album, “Prism,” which is due Oct. 22.

[For the record, 3:22 p.m., Aug. 21: A previous version of this post misspelled Sara Bareilles' last name as Bareillies.]